Pot for hot galvanizing and the like



Sept. 1,1942. 0. c. TRAUTMAN POT FOR HOT GALVANIZING AND THE LIKE Filed Aug. 23, 1941,

QQGOQbbQQ ITIEZ I INVENTOR.

OSCAR C.TRAUTMAN ATTORNEYS Patented Sept. 1, 1942 UNITED STATES PATENT OFFICE POT FOR HOT GALVANIZING AND THE LIKE 4 Claims.

My invention relates to improvements in structure used in melting spelter, tin and the like, and maintaining same at a desired temperature, when coating wire and the like in continuous operation by hot dipping. It is known to provide in such a structure, an inner pot within which the spelter, tin or the like is melted, and to heat such inner pot and its contents by a bath of molten lead contained in an outer pot spaced therefrom. Certain disadvantages have attended the use of such structures however. The molten lead, contained in the space between the two pots, becomes oxidized quite rapidly at the temperatures at which it must be maintained to melt the coating metal in the inner pot. Also the molten coating metal in the inner pot tends to erode the bottom thereof which preferably is of steel. When such erosion results in an opening the molten lead between the pots will flow, by reason of its greater specific density, into the inner pot and displace the coating metal of spelter or tin therein. By reason of this displacement of the coating metal it becomes necessary to suspend operations very quickly after erosion has made an opening in the steel of the inner vessel. Use of my improvements substantially prevents oxidation of the lead bath and permits use of my structure for a considerable period of time after erosion has opened a hole in the bottom of the inner pot.

To the accomplishment of the foregoing and related improvements, my invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims. The annexed drawing and the following description set forth in detail certain structure embodying the invention, such disclosed means constituting, however, but one of various structural forms in which the principle of my invention may be used.

In the drawing, Fig. l is a top view of structure embodying my improvements; Fig. 2 is a vertical longitudinal cross-sectional View of such structure; and Fig. 3 is a vertical transverse cross-sectional view thereof.

In a preferred embodiment, my said improvements are secured by joining the free edges of inner and outer pots formed of sheet steel, whereby I produce an air-tight double-walled pot, between the walls of which the heating bath is kept at temperatures desired to melt the coati ing metal supplied to the inner pot. My improvements will be readily understood by reference to the drawing and description showing a preferred embodiment of my invention.

Referring to the drawing, said preferred em- 55 bodiment of my invention discloses a double walled air-tight vessel comprising an inner pot I and an outer pot 3, in spaced relation and with their free upper edges united by a plate I. Inner pot I and outer pot 3 are formed of steel sheets pressed to desired form and welded in conventional manner. Preferably plate I will be formed of sections which are integral with a wall of one of the pots and which have free edges welded to upper free edges of the other pot. The double-walled, air-tight vessel so formed is mounted in an outside shell 4 of sheet steel within which it is supported, and heat insulated, by insulating blocks 5. Covering the insulating blocks 5 and the plate I of the double-walled vessel is a plate of steel 6. Through openings in the plate 6, short sections of three inch pipe 9 are welded in parts in the plate I. These pipe sections 9 are internally threaded and fitted with closure plugs 9.

To provide means for draining molten lead from the outer pot 3, an L shaped drain pipe 8 is mounted through the insulating blocks 5 and rotatably connected through the outer wall of pot 3. A plug 8' provides an air-tight closure for this drainage pipe 8.

Heating tubes 2 are welded at spaced intervals in the walls of outer pot 3. Electrical heating, elements 'I are inserted in said tubes 2 and are respectively connected by connectors I' with a source of electrical heating current.

Metal straps II mounted vertically on the inside of pot I provide support for devices which may be used to hold the material under treatment beneath the surface of the molten plating metal, and similarly threaded plugs IE! mounted on plate 6 at one end of the pot I provide adjustable means for mounting a device for wiping material as it emerges from the plating bath. Such devices for depressing wire under treatment and for wiping wire which has been plated constitute no part of my present invention and are not shown.

In operation lead will be supplied to the space between pot I and pot 3 by insertion through the tube sections 9, which will then be sealed by inserting the plugs 9'. Spelter, tin or similar coating metal will be deposited in the inner pot I. Through connectors 'I heating current of electricity is supplied to the heating elements I and the tubes 2 are heated until the lead is melted and attains the temperature desired for melting the coating metal in pot I.

When it is desired to drain the molten lead from pot 3, the plug 8 will be removed from the drain 8 which will then be turned to a downwardly extending position, permitting the escape of the molten lead.

The only oxidation of the molten lead will be that resulting from the oxygen enclosed when the tube sections 9 are sealed by insertion of the plugs 9.

Not only will my improvements result in preventing oxidation of the molten bath of lead, except to the extent resulting from the small quantity of oxygen enclosed with the atmosphere when the plugs 8 and 9' are inserted in sealing position, but as a result of this limited oxidation the atmospheric gas remaining in the space between the walls of pots I and 3 will tend to be at a pressure which is less than atmospheric pressure. This partial vacuum will assist in preventing the flow of molten lead into the inner pot I' when an opening is eroded in the bottom thereof. The displacement of coating material in the pot l by the inflow of molten lead from pot 3 will be very greatly reduced over that which would occur if the space between pots and 3 were open to the atmosphere. 7

It is to be understood that the inner ends of tubes 2 will be closed, or said tubes may be extended entirely across the pot 3 with an end welded in each opposite wall thereof.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided the means state'd'by the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinct' 1y claim as my invention:

1.' Apparatus for hot galvanizing and the like, comprising an outer pot of welded pressed steel sheets; an inner open-mouthed pot of similar structure positioned within said outer pot in spaced relation therewith and adapted to contain molten metal to be deposited 'upon material drawn therethrough; means joining the upper edges of said pots whereby a vessel is formed with double walls defining therebetween an air-tight space; an opening, in said means joining the edges of said pots, adapted for the introduction of lead into the space between the walls of said pots; and means operative to effect a closure of said opening.

2. Apparatus for hot galvanizing and the like, comprising an outer pot formed of steel sheets; an inner open pot adapted to contain molten metal to be deposited upon material drawn therethrough, said inner pot being formed of steel sheets and positioned within the outer pot in spaced relation therewith; a closure joining the edges of the side-walls of said pots and enclosing therewith an air-tight space; lead within said space substantially filling same; and a gas filling the remainder of said space, said gas being at a pressure less than atmospheric.

3. Galvanizing apparatus, comprising in combinationan outer pot; an inner open-mouthed pot of steel sheets, adapted to contain molten metal'to be deposited on material drawn therethrough, said inner pot being positioned in said outer pot in spaced relation therewith; means joining the edges of the mouths of said pots whereby an air-tight enclosure is formed between said pots; a bath of molten metal in said inner pot, adapted to coat material drawn therethrough; a body of molten lead in said outer pot only partially filling said air-tight closure; and electrical heating elements inserted through a wall of said outer pot into said body of molten lead.

4. In galvanizing apparatus employing two pots of sheet metal, one positioned within the other in spaced relation, with a bath of molten lead therebetween, the improvement comprising an air-tight joint uniting the marginal portions of the mouths of such pots, whereby an air-tight enclosure is formed between the pots, and a partial vacuum in the enclosure above the molten lead bath therein.

OSCAR C. TRAUTMAN. 

